Why does the Dorian mode on C have two flats?Note that the image shows a Dorian mode that starts on C (and is based on a B flat major scale), instead of a Dorian mode that starts on D (and is based on a C major scale). I don't know if the correct way to name a mode is based on where it starts (the mode's "tonic") or the major scale it's based on. I notice the image caption says "Modern Dorian mode on C" and not "of C", maybe that's important.